Phylum Porifera

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Phylum Porifera

• Sponges

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Characteristics

• Sponges are
• Asymmetrical
• Filter feeders
• Cellular level of organization nothing above
• Sessile
• Lacks true embryological germ layers

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Anatomy
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Diet of a sponge

• Tiny, floating organic particles
• Detritus
• Plankton
• Food is collected by choanocytes, distributed by
  amoebocytes

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Sponge reproduction

• Most sponges are hermaphrodites
• Sexual reproduction
• Eggs or sperm released captured by choanocytes
  larval stage free-floating or moving by cilia
  settles and develops
• Asexual reproduction
• Budding
• Fragmentation
• gemmules

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Classification

• Domain Eukarya
• Kingdom Animalia
• Phylum Porifera
• Classes Calcarea, Demospongea, Demospongiae,
  Hexactinellida

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Choanocyte
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Vocab terms

• archaeocytes (amoebocytes) - Cells with
  pseudopods, located in the mesohyl. They are used
  in processing food, distributing it to other
  cells, and for other functions.benthic - living
  at or near the bottom of the seas.choanocyte -
  also called collar cells, choanocytes line the
  inner cavity of the sponge. They have a sticky,
  funnel-shaped collar (that collects food
  particles) and a flagellum (which whips around,
  moving water). The sponge obtains its nutrients
  and oxygen by processing flowing water using
  choanocytes. Choanocytes are also involved in
  sponge reproduction they catch floating sperm.

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Vocab terms

• epidermis (pinacocyte) - the epidermis is the
  layer of cells that covers the outer surface of
  the sponge. The thin, flattened cells of the
  epidermis are called pinacocytes.flagellum - the
  whip-like structure of a choanocyte the
  flagellum moves, pushing water (which contains
  nourishment) through the sponge.hermaphrodite -
  an animal in which each adult can act as either
  the female or the male in reproduction.holdfast
  - root-like tendrils that attach the sponge to
  rocks.

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Vocab terms

• invertebrate - an animal without a
  backbone.mesohyl (mesenchyme) - the gelatinous
  layer between the outer body of the sponge and
  the spongocoel (the inner cavity).osculum - a
  large opening in a sponge through which water
  flows out of the sponge. Sponges may have more
  than one oscula.ostia - a series of tiny pores
  all over the body of a sponge that let water into
  the sponge. One of these is called an
  ostium.pinacocyte - pinacocytes are the thin,
  flattened cells of the epidermis, the sponge's
  outer layer of cells.

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Vocab terms

• porocyte - cells with pores that allow water into
  the sponge they are located all over the
  sponge's body.sessile - permanently attached to
  a substrate and unable to move on its own. Adult
  sponges are sessile.spicule - spicules are sharp
  spikes (made of calcium carbonate) located in the
  mesohyl. Spicules form the "skeleton" of many
  sponges.spongin - the flexible, fibrous fibers
  that form the skeleton of horny sponges spongin
  is located within the mesohyl.spongocoel - the
  central, open cavity in a sponge through which
  water flows.

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Figure 9.7
Ascon(oid) Sycon(oid)
Leucon(oid)
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Asconoid body structure

• Asconoid simplest body structure. Tube or vase
  shape. Seldom exceed 1 mm (.5 inch) in diameter

    Pinacocytes Choanocytes     Mesohyl
Water flow
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Syconoid body structure

• Syconoid variation on asconoid with pleats or
  folds in body wall. Increase in number of
  choanocytes. Can grow to a few cm in diameter

    Pinacocytes Choanocytes     Mesohyl
Water flow
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Leuconoid body structure

• Leuconoid can grow to over 1 m (3.3 ft) in
  diameter. Fills interior almost completely with
  mesohyl and greatly increases number of
  choanocytes

    Pinacocytes Choanocytes     Mesohyl
Water flow
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Sponge diagram and anatomy